1. Field of the Invention
The present invention relates to a portable terminal, and more particularly to a portable terminal which can reproduce simultaneously a plurality of contents each including at least one of video data, audio data and character data, an overlay output method, and a program therefor.
2. Prior Art of the Invention
In recent years, the Internet has been increasingly utilized by mobile portable terminals represented by a cellular phone. On the other hand, data broadcasting services are becoming more popular through the digitization of program broadcasting. Thus, there is a need for a mobile terminal which can utilize both the program broadcasting services and the Internet in a mobile environment.
A mobile terminal adapted to receive contents from a plurality of such information sources may reproduce simultaneously a plurality of types of reproduced data, i.e., contents exemplified by video (moving image data), data broadcasting (character data), audio (audio data), electronic mail (character data, still image data, moving image data, audio data), home page (character data, still image data, moving image data, audio data) and the like, and may also reproduce simultaneously a plurality of contents. However, since the portable terminal is made small in size for placing prime importance on the portability, it has a small display screen for displaying the contents. For this reason, it is not practical to display a plurality of contents using a plurality of windows on the display screen of the portable terminal, as is the case with a standstill television. Also, when a plurality of contents are displayed using a plurality of windows, complicated display switching manipulations are required for referencing many contents. However, it is probably very difficult to switch a plurality of displays during a movement.
A method of referencing a plurality of contents without complicated display switching is an overlay display which displays a plurality of contents (reproduced data) overlaid on a single screen. For example, when character data is overlaid on a television broadcast (video data), both data can be simultaneously referenced. A conventionally known method of overlaying character data on a television broadcast is an OSD (Oh Screen Display) system.
However, since simply overlaying character data on a video data results in difficulties in viewing both data, a proposal has been made on a distribution of respective reproduced data outputs for use in the overlay display in the OSD system.
On the other hand, techniques described in Laid-open Japanese Patent Application No. 2001-60080 store the luminance and contrast of a display device, when adjusted by the user, as well as the temperature, brightness and the like in surroundings, such that the luminance and contrast can be automatically adjusted from then on in accordance with a use situation (temperature and brightness). In this way, even if the use environment is changed, it is possible to realize a display condition highly visible for the user, i.e., highly visible luminance and contrast. This document also describes that an ID (identification information) given to each display unit (liquid crystal) is judged in addition to the temperature and brightness, such that the display condition is modified based on the ID of the display unit when it is replaced due to a repair or the like.
However, the conventional overlay display, though incorporating techniques for making a display itself more visible, has a problem in that a distribution of respective output parameters for reproduced data outputs is fixed so that each user is not allowed to flexibly change the distribution of overlay display in accordance with his taste.
For example, reproduced data to be mainly viewed or heard from overlaid information varies in occasion depending on the user's taste, type of information and the like. Specifically, assume that an electronic mail, a video data and an audio corresponding to the video data are overlaid. When the user wishes to mainly reference the electronic mail, it is readily supposed that the user will feel video data as obstructive if the video data are prominent more than necessary, and will also feel the audio as offensive. In this event, the user will think that he wants to reduce the luminance of the displayed video data recognizably, and wants to reduce or mute the audio.
However, when the user wishes to reference the video data at the next instance, the overlaid electronic mail will be regarded as obstructive, and the audio will be too small for the user to hear.
In this way, since which information (content) is mainly viewed, or to which degree of attention distribution should be set for viewing varies from time to time depending on a use environment of the user, and the like, troubles may occur when the user reproduces data if overlay output distribution settings are fixed among respective reproduced data or among respective contents.
In this regard, while the aforementioned Laid-open Japanese Patent Application No. 2001-60080 describes the technique for automatically changing the luminance and contrast in accordance with a use environment, this technique does not change the overlay output distribution settings among respective reproduced data or among respective contents. Therefore, the user is not allowed to freely set the overlay output distribution for reproduced data (content) mainly viewed by the user and reproduced data (content) not mainly viewed.
In the present invention, simultaneous reproduction of a plurality of audio data is also defined as an overlay output, together with the overlay display.